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      <title>调度、信号与 IPC - 交互式测验</title>
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      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>调度、信号与 IPC - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "根据文档，当需要在两个进程间进行大数据量且高速的通信时，哪种进程间通信（IPC）方式是最佳选择？",
    "options": [
      "信号量",
      "共享内存",
      "Socket",
      "无名管道"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档中的IPC对比表格明确指出，共享内存的适用场景是“大数据量高速通信”，并且其性能评级为最高（★★★）。这是因为它允许多个进程直接访问同一块内存区域，避免了内核态和用户态之间不必要的数据拷贝开销，效率极高。",
    "source": "文档中「四、进程间通信（IPC）：协作的桥梁」部分",
    "hint": "查阅文档中的IPC性能对比表格，哪种通信方式的性能星级评价最高？"
  },
  {
    "question": "在处理进程信号时，文档提到了SIGTERM (15) 和 SIGKILL (9)。它们之间的主要区别是什么？",
    "options": [
      "SIGTERM是用户发送的信号，SIGKILL是内核专用的信号。",
      "SIGTERM是可被捕获和处理的终止信号，允许程序优雅关闭；而SIGKILL是强制终止信号，不可被捕获或忽略。",
      "SIGKILL比SIGTERM的优先级更高，但两者都可以被程序捕获以进行清理。",
      "SIGTERM用于中断前台进程，而SIGKILL用于终止后台服务。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "SIGTERM (15) 是默认的终止信号，程序可以注册一个信号处理函数来执行清理工作（如保存数据、关闭连接），实现“优雅关闭”。而SIGKILL (9) 是一个强制信号，它会立即终止进程，进程自身无法捕获也无法阻止这个信号的执行。",
    "source": "文档中「三、进程信号：操作系统的紧急通知」部分",
    "hint": "思考“优雅关闭”的实现依赖于程序能够对信号做出反应。哪一个信号给予了程序这个机会？"
  },
  {
    "question": "在“实战案例2：优化CPU密集型任务”中，`chrt -f 99 ./real_time_task` 命令的核心作用是什么？",
    "options": [
      "将任务绑定到特定的CPU核心上运行以减少上下文切换。",
      "限制该任务可以使用的最大CPU时间，防止其过度消耗资源。",
      "将任务设置为SCHED_FIFO实时调度策略，并赋予其最高优先级（99），以确保其能优先获得CPU时间。",
      "降低任务的优先级（nice值为-99），使其不影响其他普通任务。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`chrt` 命令用于设置或查询进程的实时调度属性。选项 `-f` 指定了 `SCHED_FIFO`（先进先出）实时策略，而 `99` 是该策略下的最高可用优先级。这个命令的目的是让任务成为实时进程，使其在需要CPU时能抢占几乎所有其他非实时进程。",
    "source": "文档中「二、进程调度：CPU时间分配的艺术」部分",
    "hint": "文档中提到 `chrt` 命令是用来“设置实时调度策略”的，这与普通任务的优先级调整有什么不同？"
  },
  {
    "question": "当您需要精确限制一个应用程序（如 `memory_hungry_app`）的最大内存使用量以防止其耗尽系统资源时，应该使用文档中提到的哪种进阶技术？",
    "options": [
      "namespace 隔离技术",
      "gdb 核心转储分析",
      "cgroups (Control Groups)",
      "strace 系统调用跟踪"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中明确演示了如何使用 cgroups 来进行资源控制。通过创建 memory cgroup 并设置 `memory.limit_in_bytes` 文件，可以精确地限制一个进程组的内存使用上限。Namespace主要用于视图隔离，gdb用于事后调试，strace用于追踪系统调用，它们都不直接用于资源限制。",
    "source": "文档中「六、进程管理进阶技巧」部分",
    "hint": "文档中哪个技术名称的字面意思就与“控制”和“分组”管理资源有关？"
  },
  {
    "question": "在C语言中调用 `fork()` 函数后，根据文档的示例代码，程序如何区分当前执行的是父进程还是子进程？",
    "options": [
      "通过检查 `getpid()` 函数的返回值是否发生变化。",
      "通过 `fork()` 函数的返回值。在父进程中返回新创建子进程的PID，在子进程中返回0。",
      "通过检查一个特殊的全局变量，该变量在子进程中会被自动设置为1。",
      "父进程会收到一个SIGCHLD信号，而子进程不会。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`fork()` 的核心特性是它被调用一次，但返回两次。父进程得到的是新创建子进程的PID（一个正整数），而子进程得到的是0。文档的实战案例1中 `if (pid == 0)` 的判断正是利用了这一特性来区分父、子进程并执行不同的代码路径。",
    "source": "文档中「一、进程：程序运行的基本单位」部分",
    "hint": "观察“实战案例1”中的 `if (pid == 0)` 判断语句，它的作用是什么？"
  },
  {
    "question": "根据文档中提到的“信号处理三原则”，以下哪项操作最不适合在信号处理函数（如 `sigterm_handler`）中直接执行？",
    "options": [
      "调用 `printf()` 打印日志信息。",
      "设置一个全局的原子标志位，通知主循环进行清理。",
      "关闭一个已经打开的文件描述符。",
      "直接调用 `_exit()` 快速退出程序。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "文档强调了“保持处理函数简单”和“避免不可重入函数”。`printf()` 是一个复杂的I/O函数，它在内部可能会加锁或分配内存，不是异步信号安全的（async-signal-safe）。在信号处理函数中调用它可能导致死锁或未定义行为。最安全的做法是只在处理函数中做最少量的工作，比如设置一个标志位。",
    "source": "文档中「三、进程信号：操作系统的紧急通知」部分",
    "hint": "文档中提到要“避免不可重入函数”，思考一下哪个选项涉及的操作最为复杂且可能引起副作用。"
  },
  {
    "question": "在“五、综合实战：构建高并发监控系统”的架构设计中，采集进程与控制进程之间使用了多种通信方式，但不包括以下哪一种？",
    "options": [
      "信号 (Signal)",
      "Socket",
      "共享内存 (Shared Memory)",
      "消息队列 (Message Queue)"
    ],
    "correctAnswerIndex": 1,
    "explanation": "根据该部分的架构设计图 `[采集进程] --信号--> [控制进程] --共享内存--> [Web展示进程]` 并且采集进程和控制进程之间通过消息队列进行通信 `└--------消息队列------┘`。整个架构图中并未提及使用Socket在采集进程和控制进程之间通信，Socket通常用于跨机器通信，而此架构是单机内部协作。",
    "source": "文档中「五、综合实战：构建高并发监控系统」部分",
    "hint": "仔细观察该部分的架构设计图，看看采集进程和控制进程之间有哪些箭头和标注。"
  }
];
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        let score = 0;
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            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

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                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  